Catheterization has become one of the most widely used procedures in cardiovascular analysis and treatment. For example in abdominal aneurism repair a stent is placed in an aneurism, which is a weakened part of the abdominal aorta, to prevent further widening and ultimately rupture of the aneurism.
In the case of a so-called Fenestrated EndoVascular Abdominal aneurism Repair (FEVAR) procedure, the renal arteries need to be stented as well. Here, a combination of catheters and guide wires is used to bring the stent into position: First a soft guide wire with a pre-formed tip and a catheter are used to navigate to the renal arteries. In this step often several guide wires, each with a different stiffness, are tried before the surgeon succeeds in positioning the tip of the guide wire and catheter in the renal artery. After this step, while keeping the catheter in position, the soft guide wire is removed and a stiff guide wire is introduced. When the stiff guide wire is in place, the catheter is removed and a catheter with the stent is railed over the stiff guide wire in order to position the stent in the renal artery. Hereby it is essential that the guide wire is sufficiently stiff in order to be able to guide the catheter with the stent.
US 2002/0013550 A1 discloses an apparatus having a steerable distal end portion for insertion in the body lumen which comprises a superelastic shape memory member. Heating the superelastic shape memory member inside the body lumen caused it to increase in stiffness and tend toward a memorized shape, and subsequent discontinuation of heating causes the superelastic shape memory member to decrease in stiffness.
WO 2013/116096 A1 discloses methods for determining aggressiveness of a cancer and treatment thereof. An apparatus used in these methods comprises a light source and at least one optical fiber for transmitting the light. For redirecting the light onto tissue, the optical fiber has a blazed fiber Bragg grating with obliquely impressed index changes that are at a non-perpendicular angle to the longitudinal axis of the optical fiber.
U.S. Pat. No. 5,662,621 discloses a guide catheter, wherein the catheter shaft can be changed between a generally ductile state and a relatively stiff state through exposure to light. The ultraviolet or laserlight rays change the guide catheter from a relatively stiff state to a softened, ductile state.
US 2008/0019657 A1 discloses a system for diffusing light from an optical fiber coupled to a light source, comprising a polymer element adapted to be connected to the optical fiber and having incorporated a scattering element, wherein the scattering element diffuses the light.
US 2004/0106898 A1 discloses a photothermal actuator comprising an optical fiber bundle, a light inputting apparatus, and a thermal receiving element. The thermal receiving element is provided on the part of an outer surface of the optical fiber bundle. The thermal receiving element is heated by absorption of the light so that the thermal receiving element and the part of the optical fiber bundle are stretched, whereby the optical fiber bundle and a tube, in which the optical fiber bundle is inserted, are bent.